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Role of histone H3 lysine 27 methylation in X inactivation   总被引:1,自引:0,他引:1  
The Polycomb group (PcG) protein Eed is implicated in regulation of imprinted X-chromosome inactivation in extraembryonic cells but not of random X inactivation in embryonic cells. The Drosophila homolog of the Eed-Ezh2 PcG protein complex achieves gene silencing through methylation of histone H3 on lysine 27 (H3-K27), which suggests a role for H3-K27 methylation in imprinted X inactivation. Here we demonstrate that transient recruitment of the Eed-Ezh2 complex to the inactive X chromosome (Xi) occurs during initiation of X inactivation in both extraembryonic and embryonic cells and is accompanied by H3-K27 methylation. Recruitment of the complex and methylation on the Xi depend on Xist RNA but are independent of its silencing function. Together, our results suggest a role for Eed-Ezh2-mediated H3-K27 methylation during initiation of both imprinted and random X inactivation and demonstrate that H3-K27 methylation is not sufficient for silencing of the Xi.  相似文献   
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The effect of oxygen on the levels of glutathione, an important antioxidant, in must and wine was studied using a novel LC-MSMS method for the analysis of reduced and oxidized glutathione. This study found that the storage of grape juice at high SO2 and ascorbic acid levels at -20 degrees C did not lead to a decrease in reduced glutathione levels. The effect of varying the oxygen levels in South African white grape juices, which included a reductive treatment (less than 0.3 mg/L dissolved O2 added), a control treatment (between 1.0 and 1.5 mg/L dissolved O2 added), and an oxidative treatment (3.5-4 mg/ L dissolved O2 added, without SO2) on reduced glutathione levels in the juice and resulting wine was also investigated. A custom build press was used to press whole bunches of two different Sauvignon Blanc and Colombard grapes. Alcoholic fermentation and oxygen additions to the must led to lower reduced glutathione levels in the wine. Reduced glutathione levels were only significantly higher in the wine made from reductive juice that had the highest initial reduced glutathione levels in the grapes.  相似文献   
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为分析簇毛麦6VS导入小麦背景后对品质的影响,利用普通小麦簇毛麦T6VS·6AL易位系和地方品种辉县红构建的一套小麦F8重组近交家系(RIL)群体,通过分子标记结合白粉病抗性鉴定,筛选出66个包含和94个不包含T6VS·6AL的纯合家系,并分别组成两个亚群体,于2005-2006年分别在江苏南京和河南郑州通过随机区组设计(各3个重复)进行14个品质性状差异比较。结果表明,3对高分子量麦谷蛋白基因在群体及其两个亚群体中均符合1∶1分离。方差分析发现,T6VS·6AL亚群体面粉平均吸水率、面团稳定时间、最大抗延阻力和50 mm处抗延阻力均显著高于非T6VS·6AL亚群体,揭示该易位系对这些性状表现正向效应;T6VS·6AL亚群体籽粒平均容重、面粉峰值黏度和面团弱化度显著低于非T6VS·6AL亚群体,揭示该易位系对这些性状具有负向效应,而T6VS·6AL亚群体面粉平均蛋白质含量、干面筋、湿面筋、出粉率、形成时间、拉伸面积和延伸度与非T6VS·6AL亚群体无显著差异,揭示该易位系对这些性状影响较小。  相似文献   
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Globally, amphibians are among the least appreciated vertebrates and are often negatively perceived by the general public. Such attitudes are particularly prevalent in South Africa, where fear, superstitions and myths associated with frogs are pervasive in some cultures. These attitudes could have harmful consequences both for the animals concerned and conservation efforts. This study aimed to investigate attitudes to frogs throughout South Africa across multiple age and ethnic groups. We used a multi-language survey in both hard-copy and online versions. Respondents (n = 2 295) comprised both genders across six age groups and five ethnic groups. A functionalist approach using structural equation modelling was used to assess how liking of frogs and cultural beliefs varied with socio-demographic factors. Attitudes varied significantly between groups, with males more likely to like frogs than females and age and level of education also significantly linked to liking. The influence of cultural beliefs and lack of knowledge also directly influenced negative attitudes towards frogs. More than 60% of respondents expressed an interest in learning more about frogs, indicating an opportunity for improving attitudes through educational outreach. The findings of this study can be used to inform current efforts to protect amphibians in South Africa through social interventions.  相似文献   
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The mean group size of kudus in an agricultural area was 3,9 and noticeably affected by hunting. A low male: female sex ratio was also recorded, but did not influence fecundity negatively.  相似文献   
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兰旗榆为白榆的一个地理生态变种,在锡盟浑善达克沙地及其南缘的镶黄旗、正镶白旗、正兰旗等地区生长表现突出。该树种较之其它的白榆品种具有抗旱、抗寒、抗风沙,物候期早,所需积温低以及生长迅速等优良特性,对我区北部干旱草原气候生态条件适应能力强,在草原造林中有着其它树种不可替代的地位和作用,建议大力推广。  相似文献   
8.
中国正在不断推进农村绿色经济转型与乡村振兴战略,田园综合体等各种以生态环境为导向的农业开发模式是乡村振兴建设的新途径,驱动农业固碳减排的同时,也带动着传统农业不断向现代农业发展的转变。以EOD(Ecology-Oriented-Development,生态环境导向的开发)模式的上海市金山区枫泾镇郊野村庄田园综合体为研究对象,在现场调研与数据统计的基础上,分析了园区内的碳输入和碳输出以及碳在园内各区域间的流动和储积;同时,根据碳源和碳汇清单和估算结果,分析了田园综合体各区的碳平衡特点。结果显示,上海市金山区郊野村庄田园综合体2021年碳平衡表现为净碳汇区,净碳汇量为152.09 tC,其中排放量为588.79 tC,碳固定量为740.88 tC。田园综合体内,作物种植区通过低碳有机种植模式成为净碳汇量最大的区域,净碳汇量185.76 tC;水产养殖区通过高效的水草多级循环利用模式净碳汇量达62.20 tC;高空间利用率的立体农业区因农肥的碳排放量大表现为碳源区,净碳汇量为-10.81 tC;生产生活区是最大的碳源区,净碳汇量达-85.05 tC,人类文旅活动是其中最大的碳排放源。分析结合该田园综合体的碳流动,提出了发展高物质循环利用率、高空间利用率、低碳有机种植模式和农业科学管理四个农业降碳增汇的方向。  相似文献   
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There is limited information available on the morphology of the thoracic limb of the ring‐tailed lemur (Lemur catta). This study describes the morphology of the thoracic limb of captive ring‐tailed lemurs evidenced by gross osteology and radiography as a guide for clinical use. Radiographic findings of 12 captive ring‐tailed lemurs are correlated with bone specimens of three adult animals. The clavicle is well developed. The scapula has a large area for the origin of the m. teres major. The coracoid and hamate processes are well developed. The lateral supracondylar crest and medial epicondyle are prominent. The metacarpal bones are widely spread, and the radial tuberosity is prominent. These features indicate the presence of strong flexor muscles and flexibility of thoracic limb joints, which are important in arboreal quadrupedal locomotion. Furthermore, an ovoid ossicle is always seen at the inter‐phalangeal joint of the first digit. Areas of increased soft tissue opacity are superimposed over the proximal half of the humerus and distal half of the antebrachium in male animals as a result of the scent gland. Knowledge of the morphology of the thoracic limb of individual species is important for accurate interpretation and diagnosis of musculoskeletal diseases.  相似文献   
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